The report that the π-cation radical complexes of 5,10,15,20-tetra(2,6-dichlorophenyl)porphyrinates have a near degenerate 2 A1u/2A2u ground state has led us to examine their molecular structures. We wished to explore whether this near degeneracy leads to unusual structural features, namely, an alternating bond distance pattern in the 16-membered ring. The X-ray structure of the zinc complex of 5,10,15,20-tetra(2,6-dichlorophenyl)porphyrinate has a possible alternating bond distance pattern that could result from a pseudo-Jahn−Teller effect of coupled A1u and the A2u electronic states. In our attempts to prepare and crystallize additional π-cation radicals, we found an unusual reactivity at the molecular periphery of these porphyrin derivatives. The copper complex of 5,10,15,20-tetra(2,6-dichlorophenyl)porphyrinate reacts with thianthrenium perchlorate to give a β-thianthrenium derivative. The zinc complex reacts with iodine/silver perchlorate yielding neutral β-iodinated derivatives. We report the structure of the thianthrenium derivative [Cu(TCl2PPTh)]ClO4 and a symmetrically substituted β-tetraiodo derivative [Zn(TCl2PPI4)]. Crystal data:  [Zn(TCl2PP•)OClO3 ]·CH2Cl2·2C6H14, monoclinic, space group Cc, a = 12.516(2) Å, b = 21.327(3) Å, c = 22.764(3) Å, β = 98.281(13)°, V = 6012.8(16) Å3, Z = 4; [Cu(TCl2PPTh)]ClO4·CHCl3·C6H5CH3, orthorhombic, space group Pca21, a = 14.7625(18) Å, b = 12.220(2) Å, c = 33.672(5) Å, V = 6074.6(16) Å3, Z = 4; [Zn(TCl2PPI4)(THF)2]·2THF, triclinic, space group P1̄, a = 9.941(2) Å, b = 11.615(2) Å, c = 14.340(3) Å, α = 99.11(3)°, β = 103.27(3)°, γ = 106.61(3)°, V = 1499.1(5) Å3, Z = 1.

The molecular structure of the formal iron(IV) porphyrinate derivative, [[Fe(TTP)]2N]SbCl6 (TTP = tetratolylporphyrinate), is reported. The structural parameters are compared to the previously reported species [Fe(TPP)]2N, in which the iron oxidation state is +3.5. Both the equatorial and axial bond distances in [[Fe(TTP)]2N]SbCl6 are slightly shortened and consistent with an increased formal charge on iron. The value for the axial Fe-N distance is 1.6280(7) A, and the average value of the equatorial Fe-Np distances is 1.979(5) A. The Mössbauer isomer shift decreases upon oxidation, again consistent with an increase in formal charge. Values for the isomer shift at room temperature are -0.13 mm/s for [[Fe(TTP)]2N]SbCl6 and 0.04 mm/s for [Fe(TTP)]2N. Crystal data for [[Fe(TTP)]2N]SbCl6 are as follows: orthorhombic, space group Fddd, Z = 8, a = 23.689(2) A, b = 31.056(3) A, c = 22.7788(18) A.

p-Tetrakis(4-nitrophenylazo)tetrahydroxytetrathiacalix [4]arene and p-tetrakis(phenylazo)tetrahydroxytetrathiacalix[4]arene were prepared and fully characterized using 1 H and 13 C NMR, mass spectroscopy, thermogravimetric analysis and differential scanning calorimetry. The solid-state structure of p-tetrakis(4-nitrophenylazo)tetrahydroxytetrathiacalix[4]arene was investigated by single crystal X-ray diffraction. It crystallized in the triclinic system (space group: P1 ¯). z-Scan experiments were performed on the p-tetrakis(4-nitrophenylazo)tetrahydroxytetrathiacalix [4]arene showing non linear absorption due to two photon absorption with a TPA cross-section of about 50610 250 cm 4 s per photon. Optical power limiting measurements on the p-tetrakis(phenylazo)tetrahydroxytetrathiacalix[4]arene at 532 nm (48% linear transmission) was found to limit the energy to y9 mJ.